Methods without guaranteed order

[aleclarson]

Update the docs to point out which methods don't guarantee the results will be ordered as "expected".

For example, getAll(1, 2, 3) doesn't ensure the results are ordered as [{id: 1}, {id: 2}, {id: 3}].

Another example is do(query1, query2) doesn't ensure that query1 is evaluated first.

There may be others I'm forgetting about.

Edit: Actually, it seems like do(query1, query2) always evaluates query2 first (testing with rethinkdbdash). That should be mentioned in the docs, too.